High-quality ultrathin chemical-vapor-deposited Ta2O5 capacitors prepared by high-density plasma annealing

Liu, C. H.; Chang, Shao‐Chi; Chen, J. F.; Chen, S. C.; Lee, J. S.; Liaw, U. H.

doi:10.1016/j.mseb.2003.09.030

Cited by 15 publications

(5 citation statements)

References 20 publications

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“…The maximum voltage to guarantee a 10 years' lifetime is found to be −0.65V for Al-doped Ta 2 O 5 (inset of figure 7, t bd values at 63.2% are plotted versus V s ). This voltage value (or equivalently ∼1 MV cm −1 ) seems lower than the values reported by others for high-k films [16,43], and reflects the features of rf sputtered Ta 2 O 5 -based layers and their specific in-fabricated traps manifesting as weak t 63 (V s ) dependence. Note that it was not possible to extract accurately the operating voltage for 10 years lifetime for Ta 2 O 5 due to the very small variation of t 63 with V s (figure 2).…”

Section: Al-doped Ta 2 Ocontrasting

confidence: 55%

Time-dependent dielectric breakdown in pure and lightly Al-doped Ta₂O₅stacks

Atanassova¹,

Stojadinović²,

Spassov³

et al. 2013

Semicond. Sci. Technol.

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The time-dependent dielectric breakdown (TDDB) characteristics of 7 nm pure and lightly Al-doped Ta 2 O 5 (equivalent oxide thickness of 2.2 and 1.5 nm, respectively) with W gate electrodes in MOS capacitor configuration are studied using gate injection and constant voltage stress. The effect of both the process-induced defects and the dopant on the breakdown distribution, and on the extracted Weibull slope values, are discussed. The pre-existing traps which provoke weak spots dictate early breakdowns. Their effect is compounded of both the stress-induced new traps generation (percolation model is valid) and the inevitable lower-k interface layer in the region with long time-to-breakdown. The domination of one of these competitive effects defines the mechanism of degradation: the trapping at pre-existing traps appears to dominate in Ta 2 O 5 ; Al doping reduces defects in Ta 2 O 5 , the generation of new traps prevails over the charge trapping in the doped samples, and the mechanism of breakdown is more adequate to the percolation concept. The doping of high-k Ta 2 O 5 even with small amount (5 at.%) may serve as an engineering solution for improving its TDDB characteristics and reliability.

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Section: Al-doped Ta 2 Ocontrasting

confidence: 55%

Time-dependent dielectric breakdown in pure and lightly Al-doped Ta₂O₅stacks

Atanassova¹,

Stojadinović²,

Spassov³

et al. 2013

Semicond. Sci. Technol.

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“…The field strength was based on the total film thickness (TiO 2 + interfacial layer). The value extracted from these curves is κ d , and it should be bound by the static dielectric constant (κ s ) and the optical dielectric constant (κ op ) [27]. The value of κ s is obtained directly from the C-V measurement at accumulation by κ s = Cdox Aε0 .…”

Section: Metalmentioning

confidence: 99%

An investigation of annealing on the dielectric performance of TiO₂thin films

Yang

Marino

Monson

et al. 2006

Semicond. Sci. Technol.

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The impact of annealing on the dielectric performance of TiO 2 thin films synthesized by PECVD was investigated. Films annealed between 500 and 700 • C have an anatase crystal structure, while 800 • C annealed films display the rutile phase. The optimal annealing temperature was 600 • C, which both maximized the dielectric constant and minimized the leakage current density. The intrinsic dielectric constant of TiO 2 improved from 82 ± 10 in as-deposited films to 168 ± 30 after annealing. The leakage current of optimized films was superior to the SiO 2 control samples over a range of equivalent oxide thickness. Fowler-Nordheim tunnelling and Frenkel-Poole conduction were observed in the optimized films, while Schottky emission dominated leakage current at other conditions.

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“…One of the main challenges for the technology of Gbit (and beyond) dynamic random access memories (DRAMs) is the necessity of the utilization of dielectrics with a high dielectric constant, k [1][2][3][4][5][6][7][8][9]. Among alternative high-k materials Ta 2 O 5 has been widely regarded as the most promising candidate for the storage capacitors of advanced DRAMs [1][2][3][4][5][6][7]. A significant obstacle to the integration of these dielectrics is the quality of their interface with Si.…”

Section: Introductionmentioning

confidence: 99%

Impact of Si substrate nitridation on electrical characteristics of Ta₂O₅stack capacitors

Paskaleva

Spassov²,

Atanassova

2007

J. Phys. D: Appl. Phys.

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A comparison of the effect of rapid thermal nitridation (RTN) of the Si surface in N2O and NH3 ambient at different temperatures (700–850 °C) on the dielectric and electrical characteristics of thin (∼20 nm) Ta2O5 stacks has been made. The electrical parameters of capacitors (film permittivity, oxide charge, densities of bulk traps, interface and slow states, leakage current) are discussed in terms of the impact of N incorporation in the interface region. The films on both types of RTN-treated Si exhibit ∼100 times lower leakage current than Ta2O5 on bare Si, but among the two RTN processes NH3 nitridation is more beneficial since only it simultaneously increases also the stack permittivity. This improvement in parameters is suggested to be due to a real nitridation of Si surface which occurs under the NH3 rapid thermal process. RTN in N2O does not produce resistance to the oxidation substrate and it could explain the observed lack of stack dielectric constant improvement. The composition of the interfacial layer under NH3 RTN appears to be TaSi-oxinitride-like, while the interface region at N2O-nitrided Si seems to be SiO2-like. Each RTN process, however, modifies the Si surface and constitutes a specific interface layer different from that at the bare Si substrate. The composition of this layer defines parameters of the traps close to the substrate, the barrier height at the Ta2O5/interface layer and influences the conduction mechanisms in the stacks.

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High-quality ultrathin chemical-vapor-deposited Ta2O5 capacitors prepared by high-density plasma annealing

Cited by 15 publications

References 20 publications

Time-dependent dielectric breakdown in pure and lightly Al-doped Ta₂O₅stacks

Time-dependent dielectric breakdown in pure and lightly Al-doped Ta₂O₅stacks

An investigation of annealing on the dielectric performance of TiO₂thin films

Impact of Si substrate nitridation on electrical characteristics of Ta₂O₅stack capacitors

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High-quality ultrathin chemical-vapor-deposited Ta2O5 capacitors prepared by high-density plasma annealing

Cited by 15 publications

References 20 publications

Time-dependent dielectric breakdown in pure and lightly Al-doped Ta2O5stacks

Time-dependent dielectric breakdown in pure and lightly Al-doped Ta2O5stacks

An investigation of annealing on the dielectric performance of TiO2thin films

Impact of Si substrate nitridation on electrical characteristics of Ta2O5stack capacitors

Contact Info

Product

Resources

About

Time-dependent dielectric breakdown in pure and lightly Al-doped Ta₂O₅stacks

Time-dependent dielectric breakdown in pure and lightly Al-doped Ta₂O₅stacks

An investigation of annealing on the dielectric performance of TiO₂thin films

Impact of Si substrate nitridation on electrical characteristics of Ta₂O₅stack capacitors